Rock-drill



(No Model.)

L. S. WOODBURY.

ROCK DRILL. No. 319,045. Patented June 2,1885.A

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'icinrrnn Sterns Fernau* @terreno LEANDER S. VOODBURY, OF CAL-UNET, MICHIGAN.

ROCK-DMU...

BPECIFICATIQN forming part ci' Letters Patent No. 319,045, dated June 2, 1885.

Application filed December E29, 1F84.

IZ" 0 @ZZ whom, it may concern.-

- Be it known that I, Lnannnn S. Woon BURY, a citizen of the United States, residing at Calumet, in the county of Houghton and State of Michigan, have invented new and useful Improvements in Rock-Drills, set fort-h in the annexed specification.

My invention relates to that class of drills used in mines, quarries, Src., in which the motion of the piston is reciprocating, and the motive power air or steam pressure. Its ob jects are, first, to get a long and rigid guide i'or the piston-rod; second, to absolutely prevent the escape of the air or steam pressure around the rod without the use of the ordinary stufling-box, gland, and packing; and, third, by reason ot this to get a more perfect cushion upon the end of piston at the bottom ot' its stroke. These objects are accomplishet with the devices illustrated in the accompanying drawings, in which- Figure 1 is a longitudinal section on line a: a", Fig. 3. Fig. 2 is a longitudinal section on the same line,showing the old method of gland and packing. Fig. 3 is a plan oi' the head D and ring It, Fig. l, looking from the inside. Fig. a is a plan of the ring S, Fig. l, looking from the inside.

Similar letters refer to similar parts throughout the views, in which- A is the air or steam cylinder, the lower end only being shown. B is the lower end of the piston-head, and E a packing-ring in the same. C is the piston-rod, attached in any suitable way to the head B, and to the lower end of which is attached the drill. D is the lower cylinder-head, extended downward to form a guide for the rod. R is a ring iitted into the end of the head D, for the purpose of holding the packing-ring S. S is a paekingring ot' some yielding material, as leather, where air-pressure is used or vulcanized fiber for steam. F F are bolts, which extended pass through the upper head G isa recess for the purpose of dividing the bearing-surface and holding some self-lubrieating substance, as wool or felt, which .is kept saturated with oil. l?, Fig. 2, is packing within the gland H, and is the old method (No model.

of preventing the escape .of air or steam from below the pistonhead around the rod.

Having thus described the parts and their objects, I will proceed to describe their operation and the necessity for them.

In using rock-drills in mines or quarries the surface of the rock which the drill is to penetrate is usually uneven, and seldom square with theline of motion ofthe drill, so that in making the blow the drill is thrown out of its line ot' motion. It is also often the ease 'that the drill runs to one side of the direct line of motion. In all such cases, and in fact whenever the drill from any cause is thrown out oi' its true line of motion, the cylinder being held more or less rigidly, the piston is crowded hard against the cylinder head. Referring, now, to Fig. 2, theV ei'iect of this in the old device will be readily seen. The strain coming rst at the extreme end, in this ease comes upon the nut or gland H, the bearing in which from m to a is short, and in consequence of which it soon becomes so worn as to cease to be a support to the piston, the lateral strain of which then comes upon the head D, Fig. 2, which in turn becomes badly worn. Again, the nut H, being screwed onto the head D, is not at its best perfectly rigid; but it soon becomes worn by use, and though screwed up hard against the packing P, the constant jar and shock frequently loosens it, so that for these reasons also it ceases to be a support for the piston-rod, with results above described. Serious evils result from these causes. First, as the head D and nutHwear away the lateral strain is brought upon the piston head and cylinder, as a consequence of which the cylinder wears most at the lower end, and soon becomes more or less tapering, making it difficult to keep the piston tight; second, the drill striking the rock is supposed to limit the stroke ot' the piston, but from various causes-such as improper feeding or a broken drill-it does not always prevent the piston from striking the cylinder-head, the result of which is often to disable the drill. To prevent this, the piston is supposed to cushion upon the air remaining in the cylinder, as in space K, Fig. l; but this space is small, and the air must be absolutely confined to make IOO 2 clanes the cushion effective. Now, when the head D becomes worn, as above described, even though the packing P is so tight as to allow no escape of air beyond it, the air has a chance to expand into the annular space around the piston-rod, caused by the wear of the head D, as before described, and this greater space, into which the air can expand, prevents compression sufficient to give the desired cushion,

and so the piston frequently strikes the cyl' inder-head and damage ensues. In addition to this the shaking loose of the gland H referred to loosens also the packing P, causing a leakage which absolutely prevents any compression in the cylinder. If the nut H is screwed up to make the Vpacking P perfectly tight, two evils follow: First, afriction is createdaround the rod, which materially lessens the efciency ofthe drill by reducing both the number and force of the blows; second, the continued compression ofthe packing P around the rod wears the rod considerably. This not only augments the difficulty of obtaining a cushion occasioned by the wear of the head, but makes it difficult to keep the packing itself tight, as the wear is more in the center of the motion than at each end, due to a variable length of stroke.

Referring, now, to Fig. lit Will be seen how my device obviates the derangement above specified and described.

First, the head D is in one piece, held rigid- 1y with the cylinder, and the wearingsurface being largely increased where it is m ostneeded, the durability of the head is much greater than the old device herein described, and as there is no friction around the rod due to packing, the wear of the rod is reduced to the minimum, and for the same reason the number and force of the blows are increased. Vhen the head becomes so worn as to require repairs, it is much. more cheaply replaced, for, beingin one piece, the cost of construction is reduced to a minimum. This is important, as the expense of repairs in the partsin question and the delays occasioned thereby are alarge item in the cost of using this class of machines. The

recess O, being filled with felt or wool saturated with some lubricant, serves to keep the rod well lubricated and clean.

Second, the packing ring I being of some yielding material, any pressure within the space K keeps it close to the rod, effectually shutting off all escape from such pressure around the rod, and so far as leakage in that direction is concerned, the cushion desired for the purpose before described is perfect and effective, while the friction upon the rod is reduced to a minimum. This packing-ring is formed in a die or by any other method that will make it uniform in shape, and for purposes of repair the ring is split in one place in such a manner that it may be opened and sprung around the rod, the ends overlapping each other, so that when brought into place and confined by the ring R, itis asl effect-ive as if it were uncut.` This enables the user of the drill to replace the ring I, when desired, by simply loosening the bolts F and sliding the head D down the rod. In practice this ring costs less than the packing required for a stuffing-box, as in Fig. 2, while it lasts longer and compensates for the wear of the rod without undue friction.

I am aware of the use of fibrous packing in the inner end of a cylinder-head, as in holding and operation are all diiiferent, and I make no claim upon the cylinder-head D as being in one piece.

lVhat I claim, and d esire to secure by Letters Patent, is-

In a rock-drill, the combination of the head D, recessed, substantially as shown, for the purpose of self-lubrication, the packing-ring S, formed substantially as shown, the ring R, for holding the same, with the cylinder A, and piston-rod, C, all arranged substantially as shown, and for the purposes set forth.

LEANDER S. VOODBURY.

Vitncsses:

JAS. M. MriRToN, F. G. CoGGIN. 

